"The concern that we have now is based on information we have that they're considering providing lethal support," Blinken told CBS's "Face The Nation."

Asked what lethal support would entail, he said "everything from ammunition to the weapons themselves."

Blinken made similar comments in a series of interviews with American television from Germany, where on Saturday he attended the Munich Security Conference and met with his Chinese counterpart, Wang Yi.

He told Wang then that "if China provides material support to Russia or assistance with systemic sanctions evasion," there will be consequences, a State Department official said.

Taken together, the US comments appeared to be among the clearest warning yet that China might be poised to go beyond rhetorical, political or diplomatic support for Russia and be ready to help arm it in its nearly year-old fight against Ukraine.

Appearing Sunday on ABC, Blinken emphasized that US President Joe Biden had warned his Chinese counterpart, Xi Jinping, as long ago as last March against sending weapons to Russia.

Since that time, "China has been careful not to cross that line, including by holding off on selling lethal weapons systems for use on the battlefield," according to an administration source familiar with the issue.

A top Republican senator who attended the Munich conference, Lindsey Graham, said it would be a serious mistake for China to provide Russia with weapons -- especially at a time he said he has never been more sure Ukraine will prevail.

Doing so now, he said, would be akin to buying tickets on the Titanic as it was sinking.

Graham, known as a well-informed foreign policy hawk, also said he had strong indications that the US will soon announce plans to train Ukrainian fighter pilots.